Fig. 4.

TG2 activity is required for the survival of doxorubicin-treated cells. (A) HEK293 cells and HEK293 cells stably transfected with wild-type TG2 (293-TG2) or an active-site mutant of TG2 (293-C277S) were treated with doxorubicin (1 μg/ml) for 24 h. Each sample was analyzed for intracellular TG2 activity. (B) The HEK293, 293-TG2 and 293-C277S cells were treated with doxorubicin (1 μg/ml) for 48 h, and the extent of cell death was evaluated by trypan blue exclusion staining. The data represent the mean values ± standard deviations based on 3 independent experiments. (C) Cells were treated with 1 μg/ml doxorubicin for 48 h, and the TG2 expression and cleavage of caspase-3 were subsequently determined by Western blot analysis. ^*, p < 0.05; ^**, p < 0.01.